ive posted this before but noone responded hopefully ill get help this time. when i put my car into gear from park to drive it jumps almost, it feels like the whole drivetrain bangs into place. if its warm and ive driven it a few times that day its not that bad, my tranny is good, my ujoints seem* ok tranny mount is new and every time i put it into gear i have to put it into to nuetral first because it sems to lessen the bang and then i let off the brake when i put it into drive so the damn car doesnt absorb the whole jolt. it idles in park at like 7-800 then in drive like 550 600rpms. anyone have any insight.

 

Depending on how bad it is, it could be if you have a high HP car that it's simply the energy in the Torque Converter being transferred to the drivetrain as putting it into drive pulls it down from 800 to 600 rpm. A looser torque converter will usually minimize this.

 

my car only has whats listed in the sig it a form 350. is this normal, also i recently cracked the stock flexplate and had to have a new one installed(b+m) and i am just hoping its not from this jolting causing stress.

 

Well im not sure if it is normal either, i have a 91 formula and it jumps when its cold, but only into reverse. If i go park to drive when its cold nothing, shifts normal. But if i go park to reverse .. woo hoo hold on to something lol. I semi solved it by just backing in to parking spots when i know its going to be sitting for awhile, or letting it warm up. Like you said i i checked all my mounts and everything and i cant figuer it out either. The transmission i just put in about 1 year ago with a new 2200 stall converter. The thing is stock so i know its not because i have a ton of hp's making it jump. Its kinda wierd though 2 of the same cars haveing the same problem but one going in drive and the other in reverse. Just thought id post to let you know your not alone. Hopefully someone has a answer cause id like to know too.

Matt

 

my dads 84 sliverado 4x4 does the same thing, it has done it for years, warm or not, and never had a problem with it....

 

you would think withthe amount of posts on this there wouldbe a solid answer on the boards which is incorrect i toohave this prob. when i got from park to either drive or reverse it jumps also get a slight clunk when it downshifts from 2nd to 1st. checked everthing but nothing seems wrong the only thing i haven't checked is where the driveshaft enters the tailshaft of the tranny.

 

I sympathize with you guys, I've got the exact same problem. It's so bad, you'd swear someone hit you about 10 mph in my car's ****.

I'm yet to figure out what the problem is with mine, but the suggestions I've been getting is that my rear brakes are wearing thin, and that the rear wheels are chirping slightly when the transmission engages. Thus the car jumps...

I'm tearing into the drums tonight. If new brakes happen to be the fix, I'll let you know. Otherwise, best of luck.

 

its the trans mount.


when the trans mount it shot, the trans has some twisting movement to it before it locks into place.


so when you go from park to drive or drive to reverse, anything that starts applying power to it, it moves, then slams to a stop on the mount.


a new trans mount should fix it.

 

The problem it not your tranny mount, your u-joints. or your torque converter. It's your rearend the backspacing for your ring and pinion gears is off.... It from hoping in your car starting it, throwing it in to gear (For years) before its ready.

When your first start your car it idles high (Basic function) then after a minute or so it comes down to normal idle...Well if you (Or the previous owner) was impatient not letting it idle down before put it in gear that would put all that extra force on the differential and over time pitch the backspacing thus giving you the clunk, or bang......

Hope this helps.

P.S. Manual tranny's rarely have this problem because of the clutch.

 

So if its the rearend, what should be done to fix it? Will it over time ruin the rear?

 

eventually yes.. The only thing is to have someone readjust the backspacing....

basicly when you put your car in gear (more so in reverse because gears are now spinning with the curve) the play between your brakes that keep the car from moving and your differential are now brought to light.

 

And by the way after so many clunks (or if your still in the jumps stage and not to the clunks yet) your rearend will start to whine (for those who need clarification thats sort of a high pitch sound..lol) not to noticable unless mataining a constant speed just cruisin....

 

eventually all the banging and clunking will lead to shearing off a few teeth from the ring and pinion gears which at that point you have a really really big paper weight...or you will have to track down a new gear set (and for the love of ***) have a PROFESSIONAL adjust the backspacing or you will be throwing money away....

Hope This gives you some insight as to whats going on in your housing...


P.S. If someone has the power maybe we can name or change this to a VERY Important / Usefull Automatic Tranny Clunks and Jumps.... Or stick or something like that.

Thanks...

 

actually my 2.73 stock gears did the samething and when I removed them to have someone put in my 3.42 gears there were no teeth missing from the stocker gear set. So hopefully I may be ok I hope so. I had my tranny mount replaced with a rubber mount about 45000miles ago and since then I have been dragin at my local strip so it may also be that too. G*D I hope so!

 

That would be great if its as simple as that....(tranny mount that is)

And there is no gaurantee that you will break off teeth but the chance is there and a possiblity...I know from experience I broke 9 teeth off my ring and 5 teeth off my pinion gear. But my 92' has been clunking for years and whining for years I JUST MAKE sure I let the engine idle down before I put it into gear..

 

intresting.

so you're saying dropping into gear at a high idle will wear out the diff gears enough to cause slack....


meanwhile 1000s upon 1000s of manual trans owners who are much more harsh from a stop and from every shift dont have this problem.....



its not the common, usual wear items like U joints that have probly never been replaced, not the cheap rubber trans mounts that often fail in these cars... no... not any of the common extremely cheap to fix wear problems.


no, its the car at 1200RPM going into gear wearing out the same thick metal gears that take the stress of shifting and accelerating a 3500lb car... yea. thats it.

[/saracasm]




properly setup gears from the factory are not going to wear out from putting it in D at a high idle.

 

altho mine sounds like it comes from around where the tailshaft of my tranny is. is there a bearing or something in there that could have gone also when you jack the car up on the hoist you can see about an inch onthe end of the drive shaft that looks all shiny like its sliding in and out of the tailshaft

 

the driveshaft is suppost to slide in and out of the tailshaft.

as the car goes thru its suspension range, the distance from the back of the trans to the axle changes... so the driveshaft has to be able to slide in and out.

 

i understand that but it seems that when my car downshifts and i hear the clunk it is like the tranny kicks down and slams into something.

 

--------------------------------------------------------------------------------"its not the common, usual wear items like U joints that have probly never been replaced, not the cheap rubber trans mounts that often fail in these cars... no... not any of the common extremely cheap to fix wear problems."
--------------------------------------------------------------------------------

Gee well lets look at this for a minute................................................................
Ok now maybe this is a dumb question.. How many tranny mounts have you replaced? How many times have you had the backlash adjusted? Replaced Brake Pads? Wiper Blades? Hello Eventually even a Motor.... Every Thing wears out!

If you find this so hard to comprehend that it to someone who know a thing or two about rearends and have them take a look at it....

You also have to consider how old the car is and then consider everything that has been replaced throughout the years...Rearends generally get neglected if they have good gears.

 

now could this be due to something inthe tailshaft of the tranny is there anything to go wrong in there?

 

Not that I know of, it should just be the out put shaft...

Is it just on the downshift? And how hard is the downshift (meaning are weing doing 50 dropping down to punch it or are we doing 35 dropping into first to slow down?

We need more info

 

the downshift is normal its the clunk that isn't its just a mild downshift it is the clunk i worry about its hard engagement too from park to D and OD and R

 

SO that I am sure I understand...

Your cruisin along start to slow down as you do your tranny shifts down as it does it clunks? Or are you manually shifting down?

The park to D and or R is most like the rear end....One quick check is to put your hand on the hump (between the seats) behind the center console then shift into drive or reverse to see if you can feel what your hearing, if so tranny mount or torque arm bushing.
If not rear end

 

i just looked back at my thread and i didnt know so many people had the same problem. well mine does everything described even the hard downshift from 2 to 1 when auto shifting in drive. well i replaced tranny mount 3 months ago and i always figured it had something to do with the rearend and if you really listen you can hear the most of the noise come from the rearend when it engages into gear ill have to check it out. alright guys thanks alot and its good to know there is others out there with a similar thing happening, so its semi normal i guess.??

 

yeah my mechanic i am not sure if he knows exactly what he is talking about the clunk from 2nd to 1st is an auto shift and yes it feels and sound like it comes from around the tailshaft of the tranny so possible the mount now the jumpy when putting it into gear that is hard to determine but if you say it might be in the rear end well i will take it to a driveline shop if we have one in town and get them to check it out they will forsure be able to tell me if its shot or not

 

I would take it to a tranny shop (most good tranny shops Aamco, Cottmanand many others will do a free estimate) I would just tell them the problem see if they'll road test it and they should be able to give you a place to start.

 

I have the same problem with my 89 T/A w/ 305 TBI, when I start it in the morning, I have to wait almost a minute till i put it in gear, because if I don't when I put it in gear, it slams really hard, it idles high but I know thats the IAC motor, even when the idle comes down to about 1000, it still feels like someone has rearended me. I am afraid I am going to tear something up.

Jason

 

oh i hear ya

 

Unfortunately I don't know that there is anything to do aside from having the backlash adjusted....Someone in this thread said something about finding out what his mechanic said about it

 

yeah the back lash i think is my problem too altho i think some of the clunk comes from the tranny mount so im going to pic some of those up first

 

Has anyone had their backlash adjusted yet?

 

no i haven't had time to take it to a driveline specialist. altho i am planning on it right now i am having a hard time finding the poly tranny mounts in my area

 

what are you refering to when you say "backlash" ?? just wondering...

 

I had that problem after I lost 4th gear, and 2nd for the most part. After I got the tranny rebuilt, including new mounts, no jerking or clunking... so in my case it wasnt the rear end. Now to just get the exhaust and suspension fixed up.....

 

Backlash is the way the ring and pinion gears mesh together....
They are adjusted thru shims and with a micrometer

 

well as for mounts i picked up some energy susp torque arm and tranny mounts installing them this week will post results

 

my car did this so bad it was breakin stock replacement mounts within the same day i put them in. and this was with a stock 350tpi. i put one of those energy suspension mounts and now it just makes the car lurch forward. both my front and rear brakes arent that great so it may be a combo of everything everyone has said. but that trans died and i got a new one out of a 91 gta and it doesnt do it as bad.

 

My car does it, and another one of our cars does it too. I find it normal in anything that has a resonable amount of power. Not the transmount - new, tc- new, trans is new, Rear end was just rebuilt by my father (ase certified master tech) so its not that either, I idle around 800 warm, so its not reallythe idle speed, i donotice however that the warmer it gets the softer it is. And like somebody else said about their downshifting from 2nd to 1 theres a clunk, i have it too, and cant find out what it is, could just be clutches letting go i guess i unno, been to busy to look at it. Only does it in D (3rd) also the tourque arm mounts, and motor mounts are new too. So im coming to the conclusion thats just how its gonna work

 

I broke my TV cable today, trying to figure out a high idle problem... (yah I'm an idiot)

so I replaced it with a TV cable from an 82? or maybe an 86

and we spilled a crapload of ATF on the ground... from taking the TV cable off the tranny

now it jerks into drive, it jerks pretty good on all the upshifts...
and the shift points are all gone.... or severly out of whack...

needs adjustment would be the first thing, making sure I have the right amount of ATF is the 2nd... (it's hard to mesure, even with the dipstick)

my manual said something about the exhaust valve in the tranny (you know how much fun I had trying to hook the TV cable onto that little spring )

anyway... my 2 cents, and a plea for help

 

my v6 does this as well... but if I push on the brakes really hard, its not as bad... kinda like when you are backing up and you slowly bump into a curb... I think its just some slack in the transmission or just a crappy transmission or something with the torque convertor... I don't think I've ever driven a car that jumps like this...

Don't know if this will help, but if you are getting clunks when downshifting (all the time) then it could be that (torsion?) bar, that runs from the rear end, to the tranny mount... I think it's kinda like a factory traction bar... anyways, the rubber stuff in the tranny mount ALWAYS comes out... like twice a year for me... this keeps the rear end straight, because when you accelerate, or downshift, of let go of the gas real quick, or brake real quick.. you get a nice thud feeling in your bones... right where the console is...

but I think that most everyones problem is the tranny itself, because its so damned old... if I downshift from 4-3-2 no problem, but, depending on how fast you are going, you can get a fairly loud clunk going into first... this is with new ujoints and mounts etc... just not a new rearend or tranny...

just wait til your rearend goes out and go find a nice posi disc brake setup

 

that is whta i am about to do is grab a rear end out of a fourth gen and swap it in with the discs altho i am not sure about the stock master cylinder working for this. also my tranny is still good the clunk comes from the tranny mounts and as i stated got soem energy susp ones to fix this. i was looking at the tranny mount the other day and it had a hole in the middle that went right through it is this normal b/c my es one has no hole just solid??

 

ok... my turn...
I have a clunk, too... well, a "slam". My car slams into drive from park, especially when I don't wait for the idle to drop...

seems like a common problem. I wish that I could adjust the backlash. When I recently installed an aluminum driveshaft, I played with the rear u-joint-mating bracket that is attached directly to the differential... there was a fair amount of play. If I rotated it back and forth hard enough, I could hear the same clunking/slamming sound that we are talking about.

Transmission has just been serviced and a trans go/ pro-built shift kit install, new tranny mount, new u-joints (with the al drive shaft)...

dispite 3GTAs1TA1Z28's dripping sarcasm, I will re-quote him... has anyone had the backlash adjusted?

 

I finally fixed mine...

All I had to do was buy a 2000 WS6

seriously though, I couldn't figure out the problem on my old bird...

sounds like sloppy rear ends to me

 

yes, I think slop is the answer... it's more annoying than anything else. I mean that I don't think the diff will actually fail.....

 

Sorry about the gravedig, but this sounds like what's been happening with my car. My comprehension of things from the transmission back are not too good, with the obvious exception of a torque converter. I'm planning on switching my 2.73 gears to 3.42's- Will this fix the clunking, or will more adjustment ahveto be done?

 

i have this same problem, when i first shift from park to drive or reverse it slams pretty good but as it warms up it softens up, it only does it when im shifting from park to drive or reverse or nutreal to drive or reverse. iv got a new tranny mount, ujoints are good, tranny and rear end were serveiced within the last year

 

Ok, I've had this same EXACT problem with my 91 when I bought it with 60,000 miles on it, and it still only has 68,000 orig on the ticker. Keyword here HAD this problem (drumroll please) gentleman, change your fluid! With our cars being driven so hard regularly its rough on all the fluids and components of the driveline. As the viscosity of your transmission fluid changes with age and wear it will cause this problem. When I bought my car it would grab drive or reverse VIOLENTLY, when I brought it home the first thing was change the transmission fluid and filter...the fluid was horrible. Not only are we looking at general/harsh driving wear...but this fluid is 20 years old if it hasn't ever been changed and its overlooked more times than not. After my fluid change and a few days of driving afterwards it was just as smooth going into drive as any other vehicle I've owned. It may take more than one change over time to fix the issue as the torque convertor holds transmission fluid we can not get to and you should change your fluid at least twice for this reason. (Only took one change for me) DO NOT get your transmission flushed at a shop if you have this issue it may force derbis into your transmission and make it cease function or the shock of the all new fluid may pose the same problem. Its also suggested when you get the pan off to throughly wash it out and clean off the magnet (metal filings are normal chunks are not) use soap and water clean it as if you intended to eat out of it and make sure its completely dry/free of soap or other contaminants before you reinstall it. Good luck let me know how it works out. with any luck none of your transmissions are so far gone they need rebuilt because unfortinately that's the next step

 

Oh, for those of you with clunks upon accell/decell. Have a look at your rear transmission mount doesn't take long and its a cheap/easy fix these cars are GREAT at destroying transmission mounts thanks to the torque arm mounting to the tailshaft. If your mount is torn and you plan on staying stock just grab a ploy mount available at most every parts store for 25-30 bucks depending upon your locale. I suggest poly from my personal expirience of tearing 2 brand new rubber mounts in one week!